Method for changing the bobbins in a roving frame

ABSTRACT

A process for bobbin replacement on a flyer frame provided with a drafting frame, flyers, spindles and a bobbin rail, in which, while the flyer frame is running, a sliver end for each sliver supplied by the drafting frame is placed upon an empty bobbin sleeve. Initially only the flyers and the spindles of the flyer are driven. The flyers and the spindles are either immediately advanced in a forward direction or are initially driven backwards and after the lapse of a predetermined time period, brought to standstill and then driven forwardly, whereby the standstill of the flyers and the spindles coincide in time or are offset in time. After the start of the forward drive of the flyers and the spindles, the time-delayed drafting frame is set into operation.

SPECIFICATION CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage of PCT/DE97/01387 filed Jun. 28,1997 and based upon German national applications 196 28 667.0 filed Jul.16, 1996 and 197 17 523.6 filed Apr. 25, 1997 under the InternationalConvention.

FIELD OF THE INVENTION

The invention relates to a process for bobbin replacement on a rovingmachine provided with a drafting frame, flyers, bobbins and a bobbinrail, in which while the roving machine is running, a sliver end of eachsliver supplied by the drafting unit is applied to an empty sleeve.

BACKGROUND OF THE INVENTION

Generally in the state of the art, after a bobbin replacement on aroving machine, in which the pressing fingers generally remain inoutwardly swung positions, from the guide eye of the pressing finger endthe sliver end hanging out must be applied to the new empty sleeve. Forthis purpose the sleeve is provided with a sliver catcher region, forexample, in the form of a so-called burr strip which engages the sliverend when it is applied to the sleeve. To achieve this, the rovingmachine is set into operation whereby the pressing finger under theeffect of centrifugal force comes to lie against the sleeve.

Roving machines with single drives thus apply the driving force to allof the elements, i.e. the drafting frame, the flyers, the bobbins andthe bobbin rail simultaneously. Since the application of the pressingfinger against the sleeve and thus the acquisition of the sliver by thesleeve can be effected only when a certain minimum speed is reached, thesliver is not seized for the first few rotations. The sliver, duringthis interval, is not drawn from the drafting frame and since the latteris in operation, a sag develops in the sliver between the drafting frameand the flyer head. As a result, the sliver can loop around the flyerhead which can give rise to a breakage in the sliver when the rovingframe is not temporarily stopped and the sleeve rotated by hand. In anycase, the sag in the sliver must be eliminated by the take-up of theexcess between the flyer and the bobbin.

Similar problems are found also for roving machines with separatelycontrollable drives of the flyer, the bobbin, the drafting unit and thebobbin rail.

OBJECT OF THE INVENTION

The present invention has as its object to provide a process and acorresponding apparatus for bobbin replacement in which this problem isobviated and whereby it can be ensured that the sliver end is engaged ina reliable manner such that undesired sag between the drafting frame andthe flyer head is avoided.

SUMMARY OF THE INVENTION

This object is achieved according to the invention in that initiallyonly the flyers and the spindles (but not the drafting frame) of theroving machine are driven. The flyers and the spindles are either drivenimmediately forwardly or are initially driven backwards, are brought tostandstill after a given time interval and then are driven forwardly,whereby the standstill of the flyers and the spindles can coincide orare offset in time.

After the start of the forward drive of the flyers and bobbins, thedrafting frame which has been delayed in operation for a time interval,is set into operation.

By "forward drive" is meant the drive of the flyer and bobbin in thenormal sense of rotation while "backwards drive" of the flyer and thebobbin means rotation in the sense opposite normal rotational direction.

For application of the sliver to the sleeve only the flyers and thespindles are set in rotation preferably with the same speed, while thedrafting frame remains at rest. As a result, the pressing finger and thesliver come to lie against the sleeves without the formation of a sag ofthe supplied but not gripped sliver. Only thereafter is the draftingframe set into operation and, indeed, with a slowed supply for examplefor a length of about 5 centimeters, whereby the sliver end which hasbeen brought into contact with the burr strip, is securely engaged. Onlythereafter is the roving machine restored to its normal production rate.

The flyers and the bobbins can run with the same rotary speed for theapplication of the respective sliver ends. However, it is possible toinitially operate the drafting frame only at a reduced supply rate.

According to a further feature of the invention, the bobbin rail driveis actuated after successful operation of the flyers and bobbins orafter successful operation of the drafting frame has commenced. Themovement of the bobbin rail is, however, delayed to the latest at thepoint at which the sliver ends are gripped by the burr strips of thesleeves.

In an apparatus with separate controllable drives of the individualunits, a control unit can be provided for simultaneously operating theflyers and bobbins and for a time-delayed drive of the drafting frameaccording to the invention. The drive for the bobbin rail can also beconnected with the control unit.

In a system with a single drive, a control unit can be provided for thecoupling of the single drive with the drafting frame. Furthermore, thebobbin rail drive can be connected by a clutch operated by the controlunit, with the main drive.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features, and advantages will become morereadily apparent from the following description, reference being made tothe accompanying drawing in which:

FIG. 1 is a schematic side elevational view of a roving machine with tworows of flyers with separate and separately controllable drives for theindividual units; and

FIG. 2 is a schematic side elevational view of a roving machine with acommon drive for the individual units.

FIG. 1 shows a roving machine 1 with a drafting frame 2, flyers 3,spindles 5 and a bobbin rail 6. The flyers 3 are journaled in a flyerrail 4.

The spindles 5 carry empty sleeves 8, 8' with sliver-capturing regions9, 9', preferably in the form of burr strips. The flyers 3 have pressingfingers 15 with corresponding pressing finger tips.

The bobbin rail 6 is vertically movable in the direction of the arrowswith the aid of a bobbin rail drive 10 via a gear 11 and a rack 12.

For the drive of the spindles 5, a drive 20 with a correspondingtransmission is provided. The flyers 3 are driven via a drive 40 andcorresponding intermediate transmissions; for the drafting frame 2, adrafting frame drive 30 is provided with motion transfer elements 31.The drives 10, 20, 30 and 40 are interconnected by a common control unit50.

With the aid of this control unit 50, the flyers 3 and bobbins 5 areinitially driven, i.e. the corresponding drives 40 and 20 are turned on.Thus the system provides for the possibility that the flyers 3 and thebobbins 5 will run with the same rotary speed for application of therespective sliver ends.

After start of the forward drive of the flyers 3 and the spindles 5, thetime-delayed drafting frame 2 is set in operation via the drive 30whereby the sliver ends hanging out of the tips of the pressing fingers15 for the slivers 7 and 7' can be adhered to the respective emptysleeve 8 or 8' with the aid of the sliver capturing means 9 and 9'. Thedrafting frame 2 initially can be set in operation with a reduced supplyrate.

It is, further also possible for the movement of the bobbin rail 6 tocommence at the latest, once the sliver 7 and 7' are engaged.

FIG. 1 thus relates to an apparatus with separately controllable drives10, 20, 30 and 40 for the flyers 3, the bobbins 5, the drafting frame 2and the bobbin rail 6. The control unit 50 connected with these driveseffects simultaneous operation of the flyers 3 and the spindles 5 withtime-delayed operation of the drafting frame 2. It also allows for thepossibility that the drive 20 of the bobbin rail 6 will be connected tothe control unit 50.

FIG. 2 shows another embodiment of the invention in which the rovingmachine has a common drive 60 for the drafting frame 2, the flyers 3,the bobbins 5 and the spindles rail 6. The common drive 60 is connectedwith a control unit 50' which, in turn, is connected with a clutch 61between the drive 60 and the drafting frame 2 and with a clutch 62between the drive 60 and the bobbin rail 6. Via the control unit 50' andthe clutch 61 and 62, initially only the flyers 3 and the bobbins 5 ofthe roving machine 1' can be driven. After the commencement of theforward drive of the flyers 3 and the spindles 5, the drafting frame 2is set in operation via the clutch 61 so that the sliver ends of theslivers 7 and 7' can adhere to the respective empty sleeves 8 and 8'with the aid of the sliver capturing means 9 and 9'.

With the present invention it is ensured that with devices for theseparate or separately controllable drives for the individual workingelements or with the devices for the common drive of the individualworking elements, upon the bobbin replacement, in which each sliver endfrom a sliver supplied by the drafting unit, is applied to an emptysleeve, initially only the flyers 3 and the spindles 5 of the rovingmachine are driven. After the commencement of forward drive of theflyers 3 and the bobbins 5, with time delay, the drafting frame 2 is setinto operation via the drive 30, so that the sliver ends of the slivers7 or 7' can be adhered to the respective empty sleeves 8 and 8' with theaid of the sliver capturing burr strips 9 and 9'. There is also thepossibility of a reduced supply for a length of about 5 centimeters ofthe sliver whereby the sliver ends can be reliably engaged by the slivercapture regions 9 and 9'. Only then is the roving machine brought up tonormal production.

We claim:
 1. In a bobbin replacement process for a flyer roving machinein which roving is wound upon sleeves on spindles on a bobbin rail withflyers and spindles driven in a forward direction from sliver fed by adrafting frame to form respective bobbins, full bobbins are removed fromthe spindles and are replaced by empty sleeves, and a free end of arespective sliver is formed on each flyer, the improvement whichcomprises the steps of:(a) upon mounting of an empty sleeve on eachspindle initially driving only the respective spindle and flyer to applya respective one of said free ends to the respective empty sleeve, whilethe drafting frame is not driven to engage the free ends on therespective sleeves; and (b) thereafter driving said spindles and therespective flyers in the forward direction while driving the draftingframe for winding of respective bobbins on the sleeves.
 2. Theimprovement defined in claim 1 wherein the flyers and spindles aredriven forwardly in step (a).
 3. The improvement defined in claim 1wherein initially in step (a) the flyers and spindles are driven in abackward direction and after the lapse of a predetermined time periodthe flyers and spindles are brought to standstill and thereafter theflyers and spindles are driven in said forward direction.
 4. Theimprovement defined in claim 3 wherein said flyers and spindles aresimultaneously brought to standstill in step (a).
 5. The improvementdefined in claim 3 wherein in step (a) said flyers and spindles arebrought to standstill at different times.
 6. The improvement defined inclaim 1 wherein the driving of the drafting frame in step (b) isinitiated with a time delay following the commencement of the driving ofthe spindles and flyers in said forward direction.
 7. The improvementdefined in claim 6 wherein said flyers and said spindles are driven withthe same speed in step (a) for engagement of the free ends on therespective sleeves.
 8. The improvement defined in claim 6 wherein saiddrafting frame is driven in step (b) initially to deliver sliver to eachof said flyers at a reduced rate by comparison with the rate at whichsliver is delivered to said flyers for winding of respective bobbins onthe respective sleeves.
 9. The improvement defined in claim 6, furthercomprising the step of setting said bobbin rail into operationsimultaneously with driving of said flyers and said spindles.
 10. Theimprovement defined in claim 6, further comprising the step of settingsaid bobbin rail into operation simultaneously with driving of thedrafting frame.
 11. The improvement defined in claim 6, furthercomprising the step of setting said bobbin rail into operation onlysubsequent to the driving of said flyers and said spindles.
 12. Theimprovement defined in claim 6 wherein said bobbin rail is set intooperation only after the driving of said drafting frame has commenced.13. A flyer roving machine comprising:a bobbin rail carrying amultiplicity of spindles adapted to receive sleeves on which respectivebobbins are wound; respective flyers assigned to said spindles fordelivering sliver to said sleeves; a drafting frame for feeding saidsliver to said flyers; and control means effective during a bobbinreplacement process in which full bobbins are removed from the spindlesand are replaced by empty sleeves and a free end of a respective sliveris formed on each flyer, and connected with drives for said spindles,said bobbin rail, said flyer and said drafting frame for initiallydriving only the respective spindles and flyers upon mounting of emptysleeves on said spindles to a flyer respective one of said free ends tothe respective empty sleeve while the drafting frame is not driven toengage the free end on the respective sleeves, and thereafter drivingsaid spindles and the respective flyers forwardly while driving thedrafting frame for winding of respective bobbins on the sleeves.
 14. Theapparatus defined in claim 13 which has a common drive for the flyers,the spindles, the drafting frame and the bobbin rail, further comprisinga clutch connected to said control means and arranged ahead of saiddrafting frame.
 15. The apparatus defined in claim 14, furthercomprising a clutch connected to said control means and arranged aheadof said bobbin rail.